It is a common practice for buildings with subgrade level, enclosed spaces such as crawl spaces and/or basements to provide venting. This permits moisture to escape from the basement during warm summer months. However, it is generally unnecessary to vent these spaces during the colder winter months when the air is dryer and less moisture is seeping into the basement. Accordingly, it is preferable to close off these vents during the winter months.
To close off vents for the winter, it is generally necessary to place a cover over the vent opening. Although this is not particularly difficult, it is very easy to lose the cover. Even if the vent cover is not lost, one must store it while not in use. Also, it does generally take more time than desired to cover the vent and subsequently uncover it during the summer months.